An objective of the present invention is to enable making a liquid crystal display device thin, and to enable regional control of window brightness with power conservation. A backlight of a liquid crystal display device comprises a plate-shaped light guiding plate (20). Recesses (21) are formed on the light guiding plate (20), and LEDs (30) are housed in the recesses (21). The LEDs (30) further comprise light emitting faces (301) and rear faces. The rear faces of the LEDs (30) are brought into contact with the interior walls of the recesses (21) of the light guiding plate, and light that leaks from the rear faces of the LEDs (30) is proactively used. A resin (25) for optical coupling is positioned between the LEDs (30) and the interior faces of the recesses (21). Using the light from the rear faces of the LEDs (30) allows reducing the number of LEDs that need to be lit, allowing obtaining a liquid crystal display device with minimized power consumption.